"So we'll never protect either an individual from an attack in a New Zealand court from a legal case, or a future New Zealand government from the possibility of a legal attack, but the key thing is to get the legal framework as robust as you can bat it back."

But Cunliffe said the public needed to be able to debate those issues as well as the trade upsides.

He said Labour had not made the full text public when it signed the free-trade deal with China in its last term in office.

But it had been more open than this government during the negotiation process by including non-government organisations and unions in full, open consultation as the deal was being developed.